JUST A CASE OF `STAGE LIGHT` FOR HOCKNEY

John Russell, New York Times News ServiceCHICAGO TRIBUNE

In his large, rambling house high in the Hollywood Hills, David Hockney-painter, draftsman, printmaker, photographer, designer-sat before a model theater. Built to a scale of 1:12, it mimicked exactly the Dorothy Chandler Pavilion in Los Angeles, complete with proscenium, flies and a keyboard for the lights.

The occasion, three weeks ago, was a run-through in miniature of a new production of Wagner`s ''Tristan and Isolde,'' which premiered Sunday at the Chandler Pavilion.

The production is unlike any other. Conductor Zubin Mehta, back for the occasion with the Los Angeles Philharmonic, which he led from 1962 to 1978, never before had conducted ''Tristan.'' Jonathan Miller, the English stage director known for his provocative ideas, never before had directed an opera by Wagner.

Hockney had in mind an entirely new blending of color and light, constructed scenery as opposed to painted flats, and flexible space.

''I think that the way we depict space has a great deal to do with how we behave in it,'' Hockney said. ''When people go on about `exploring outer space,` I tell them that we`re in outer space already, if we know what to do with it.''

What he wanted on stage was space that people could walk around corners in, as distinct from a regimented, single-point perspective.

''You`d have to be an old bore not to enjoy Act 2 of Zeffirelli`s production of `La Boheme` at the Met,'' Hockney said.

''He makes it just what it is-a story of warm hearts in a cold place. But his space is literal space. What I want is to chop up space, and in `Tristan` we`re going to do it.''

The flexible space in question would be made possible primarily by an automated lighting system known as Vari-Lite. Devised for use at rock concerts, Vari-Lite is said to allow a multiplicity of palette, a freedom of control, a degree of precision and an instantaneity of response that never have been achieved before.

With a rudimentary console and a restricted palette at Hockney`s home, there was no mistaking the ease with which space could be shaped and reshaped by color and responses fine-tuned to a fraction of a second.

Color combinations previously unattainable can be summoned up at will. More important, whole sections of the scene can be metamorphosed. Others can be made to vanish. Great trees can be whisked out of sight. The very nature of ''scene-changing'' no longer has its old meaning.

''At the end of the 19th Century,'' Hockney said, ''you could have 30 or 40 men up in the flies, manipulating the lights. You couldn`t afford that today, even if you wanted to; and with these new techniques you can do a hundred times as much by just pressing a button.''

Wagner`s ''Tristan and Isolde'' needed just that reshaping and just that instantaneity of response if it was to avoid the static quality people have complained of ever since it first was performed in soft, pearly gaslight in Munich in 1865.

Wagner left stage instructions that are as detailed as they are precise, but there are long stretches in which nothing happens, in conventional terms. There also are moments at which all too much happens in a moment or two, and the action on stage appears abrupt, perfunctory and unthought-out.

Hockney at 50 has something of the reputation that he had at 25, that of a minor poet of the pool-side life, a human sundial who blanks out all but the blissful hours.

Who is he, some people have said, to tackle a supreme human achievement such as ''Tristan''?

In fact, Hockney has many of the qualifications. In the theater, as in life, he is clear-headed, straightforward and can get through to audiences no matter how large.

Anyone who can draw 270,000 visitors to an exhibition of stage designs, as Hockney did in Mexico City, has to have done something right.

It is evident from ''The Rake`s Progress'' (1975) and ''The Magic Flute'' (1978) at Glyndebourne in England, and from ''Les Mamelles de Tiresias,'' ''L`Enfant et les Sortileges'' and ''Oedipus Rex'' (all in 1981)

at the Metropolitan Opera that Hockney, the stage designer, combines a sense of historical style with a sense of wonder and awe, a total practicality and the heavy-duty good sense that are associated with his native Yorkshire in England.

And unlike many artists who are successful even in their student days, he never has stopped growing.

In his sets for ''Tristan,'' the manipulation of space relates to a late 17th Century Chinese scroll about which he recently made and narrated an hour- long film.

Although Hockney is a longtime champion of free-hand drawing from the model, he is fascinated by recent developments in commercial copying machines. One such machine played a part in the designs for ''Tristan.''

His sets for ''Tristan,'' he said, are ''both the most abstract that I`ve done and the most realistic.''

The ship, in stage terms, is a real ship. Isolde`s sofa on board in Act 1 is a real sofa, built in Saratoga, N.Y., to Hockney`s specifications. The costumes-all in velvet, to avoid reflected light-are adapted fom a 14th Century source.

Altogether, Hockney believes that he is thoroughly faithful to Wagner.

''Everything that Wagner asks for, you`ll get,'' he said. But how to manage the mercurial transitions of which Wagner was past master?

It was no small problem. After Isolde has said her last word and sinks,

''as if transfigured,'' on to the lifeless body of Tristan, there follows a long minute (65 seconds, in the Kleiber recording) for which no one has found the right visual equivalent.

What is heard from the pit is sublime, beyond either measure or expectation, but the people down front lie around like sedated picnickers.

''It`s difficult, all right,'' Hockney said. ''We did 10 versions before we got one that seemed right. It can`t be done quicker.

''We were seven months on this model here. My fee ran out after four weeks, so I suppose I`ve been subsidizing it all. But I`ve come to take rather a Wagnerian attitude to money. `Money? Who cares about money?` Besides, it`s not just new technology that makes things better. It`s love.''